Human gene regulation will be analyzed with the use of cell cultures from both normal and mutant individuals. The rates of both general and specific protein synthesis and degradation will be compared in both normal and mutant cella; and the non-genetic factors in the cell culture milieu will be identified. Galactose-1-phosphate uridyl transferase, glucose-6-p dehydrogenase, catalase, and possibly Beta-galactosidase are the specific proteins that will be studied. Inter and intraspecific hybrids will be used in certain human transferase experiments. These include those involved with chromosome localization, the possible role of regulatory genes in hepatic cells, and complementation between different galactosemic cell lines.